Drinking too much coffee can make you hear voices, warn scientists By Daily Mail Reporter
Last updated at 4:37 PM on 6th June 2011
Caffeine: Those who drank a large number of coffees were more likely to hear White Christmas in white noise Drinking coffee might help you get through a stressful day - but it could also bring on hallucinations, researchers say.
Just five cups a day may be enough to make you hear things that aren't actually there.
In an experiment, volunteers who had consumed 'high levels' of caffeine thought they were listening to Bing Crosby singing White Christmas even though the song was not being played.Experts said the study showed that the health risks of too much coffee needed to be addressed.
The researchers, from La Trobe University, Melbourne, Australia, described caffeine as 'the most commonly used psychoactive drug'.
Coffee and other caffeinated drinks such as tea and energy drinks can 'increase tendencies to hallucinate' when taken in large doses, said Professor Simon Crowe.
Professor Crowe and his colleagues measured the effect of stress and caffeine on 92 volunteers.
Five coffees a day or more were 'enough to increase their tendency to hallucinate,' the team discovered.In the tests, participants were asked to listen to a constant fuzzy sound known as white noise.
'We also told them that within the white noise there may be parts of the White Christmas song and if you hear it, press the button,' explained Professor Crowe.
'We didn't include White Christmas in the white noise but found that more people who were very stressed and had high levels of caffeine heard White Christmas.' 'There is a link between high levels of stress and psychosis, and caffeine was found to correlate with hallucination proneness.
'The combination of caffeine and stress affect the likelihood of an individual experiencing a psychosis-like symptom.
It is apparent that the health risks of excessive caffeine use must be addressed and caution should be raised with regards to the exacerbating use of this stimulant.
'Caution needs to be exercised with the use of this overtly 'safe' drug,' he added. The study may also help to explain why stress may
trigger symptoms of schizophrenia in some people, the researchers believe.